<!DOCTYPE html>
<html>
<head>
<style>
div {
	margin: 3px;
	width: 40px;
	height: 40px;
	position: absolute;
	left: 0px;
	top: 30px;
	background: green;
	display: none;
}
div.newcolor {
	background: blue;
}
</style>
<script src="http://code.jquery.com/jquery-latest.js"></script>
</head>
<body>
	<button id="start">Start</button>
	<button id="stop">Stop</button>
	<div></div>
	<script>
$("#start").click(function () {
	var myDiv = $("div");
	myDiv.show("slow");
	myDiv.animate({left:'+=200'},5000);
	myDiv.queue(function () {
		var _this = $(this);
		_this.addClass("newcolor");
		_this.dequeue();
	});
	myDiv.animate({left:'-=200'},1500);
	myDiv.queue(function () {
		var _this = $(this);
		_this.removeClass("newcolor");
		_this.dequeue();
	});
	myDiv.slideUp();
});
$("#stop").click(function () {
	var myDiv = $("div");
	myDiv.clearQueue();
	myDiv.stop();
});</script>
</body>
</html>